Phase behavior of 6-arm star (PMMA-<EM>b</EM>-PS)<SUB>6</SUB> in thin films
발표자
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초록
내용
To apply block copolymer (BCP) to nanolithography, vertically oriented microdomains in thin film are needed. When the chain architecture of BCPs was star shape, vertically oriented microdomains were obtained by using only thermal annealing. Here, we investigated the effect of the molecular weight (M) of 6-arm polymehylmethacrylate-block-polystyrene copolymers [(PMMA-b-PS)6] on the orientation of nanostructure in thin films. At smaller M, parallel orientation of microdomains was observed. This is because the entropic loss arising from the formation of vertical oriented microdomains is not large; thus the its orientation is greatly affected by a substrate. On the other hand, at larger M, the entropic penalty for parallel orientation becomes huge, resulting in vertical orientation. We also studied the film morphology depending on annealing temperature. When the film thickness of (PMMA-b-PS)6 was 1 L0, an interesting nanotubes were formed when annealing temperature was controlled.